Intravenous (IV) acetaminophen was FDA-approved in November 2010 for the treatment of acute pain and fever in adults and children ≥ 2 years. In an IRBapproved, single site study conducted by Singla, 6 healthy adult males were given IV, oral (PO) or rectal (PR) acetaminophen in a 3-way crossover design. A spinal catheter was placed for cerebrospinal fluid (CSF) sampling.
The objective was to show comparative plasma and CSF concentration-time curves in healthy adult males after IV, PO, or PR acetaminophen.
The IV group received Ofirmev® (acetaminophen) injection 1000 mg (Cadence) over 15 min. The PO group received two Tylenol® 500 mg caplets (McNeil). No approved PR suppository dose of acetaminophen higher than 650 mg exists, nor is there a 500 mg dose, therefore two Feverall® 650 mg suppositories (Alpharma) were used for the rectal group. After subjects were admitted to the clinic, a spinal catheter was placed at the lumbar level, and on the next 3 mornings, each subject received a single dose of IV, PO or PR acetaminophen in random order.
Safety assessments included laboratory tests, physical exams and spontaneous adverse events (AE).